THE idea that the earth’s physical and biological systems adjust to perturbation through feedback systems is central to James Lovelock’s Gaia theory. Let me declare upfront that I don’t subscribe to this theory because I don’t see the earth as a living entity, but rather as a place where life is lived. I do agree, however, that natural systems tend to exhibit strong negative feedback around an equilibrium point. Negative feedback is the opposite of positive feedback. It acts to oppose perturbation on a system and thus to maintain the current equilibrium. [1]
The Gaia theory is very popular including amongst many sceintists concerned about global warming notably Tim Flannery. Professor Flannery was named Australian of the Year in 2007 and is presently chairman of the Copenhagen Climate Council. The Gaia theory underpins his influential book on climate change ‘The Weather Makers’.
Given Professors Lovelock and Flannery believe in feedback systems which seek to maintain an optimal physical and chemical environment for life on earth, Gaia, it is perhaps surprising that they are so concerned about elevated concentrations of carbon dioxide causing a climate crisis.
I understand that this concern, as articulated by Professor Lovelock in his 2006 book ‘Revenge of Gaia’, stems in large part from a belief that Gaia has been so despoiled that the biological systems which would normally buffer, for example the capacity of phytoplankton and forests to draw excess carbon dioxide from the atmosphere, is no longer properly functioning.
But what if there exists a physical system, in addition to these biological systems, to prevent runaway greenhouse?
New research by Hungarian physicist Ferenc Miskolczi’s has shown that there will not be a runaway greenhouse effect because the atmosphere maintains a “saturated” greenhouse effect, controlled by water vapour content. [2] The analogy has been made to a saucepan of saturated salt solution boiling on a stove. Turn up the gas on the stove and the boiling point is not affected. Add more salt and the boiling-point is not affected, because the salt solution is already saturated. [3]
Dr Miskolczi’s work provides a detailed Gaia level empirical formulation of how the physical system works to maintain equilibrium. While American Climatologist Roy Spencer, has independently provided a nuts and bolts demonstration of possible mechanisms with respect to the hydrological cycle. [4]
So there is perhaps no longer a reason for Professor Lovelock to continue to believe that it is already too late to avoid significant global warming that will make much of the Earth’s surface inhospitable.
In summary, new findings by a Hungarian physicist and an American climatologist, interestingly both climate change sceptics, provide evidence for a physical system to support the popular Gaia theory of a world kept at an optimal equilibrium for life. [5]
And the really good news is that the critical regulating gas, water vapour, is unlikely to ever be limiting because there is just so much of it on planet earth. Indeed I think it is time James Lovelock wrote a new book and I suggest it be entitled, ‘Gaia: Saved by the Seas’.
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Important Notes and Links
My ideas for this note come from correspondence with Christopher Game and have also been significantly influenced by reading Michael Hammer. But I don’t expect them to agree with much of what I have written.
1. Michael Hammer recently commented at this blog that “Natural systems virtually all exhibit strong negative feedback around an equilibrium point.” Mr Hammer made the comment to contrast this observation with the IPCC temperature rise claims which are based on an assumption of strong net positive feedback in our climate system. Negative feedback is the opposite of positive feedback. It acts to oppose any disturbance acting on a system and seeks to maintain the current equilibrium.
http://jennifermarohasy.com/blog/2009/04/role-of-water-vapour-in-climate-change/
2. F.M. Miskolczi (2007) Greenhouse effect in semi-transparent atmospheres, Quarterly Journal of the Hungarian Meteorological Society 111(1): 1-40.
‘The Saturated Greenhouse Effect’ by Ken Gregory provides a good summary of the new theory developed by Ferenc Miskolczi .
http://www.friendsofscience.org/assets/documents/The_Saturated_Greenhouse_Effect.htm
3. Christopher Game would add that the climate process is different from a boiling saucepan in one important respect. Non-equilibrium phase transitions are a little conceptually different from equilibrium ones. The phase transition at which the climate process is pinned is dynamical in character, in contrast with the phase transition of boiling water which has a static character. Consequently the physical quantity that is pinned is not the climate temperature; it is the climatic response ratio.
4. Roy Spencer and Danny Braswell, Potential Biases in Feedback Diagnosis from Observational Data: A simple Model Demonstration, Journal of Climate.
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2008JCLI2253.1
Roy Spencer, recently commented at his blog that:
But the climate system tinkers with itself all the time, and the climate has managed to remain stable. There are indeed internal, chaotic fluctuations in the climate system that might appear to be random, but their effect on the whole climate system are constrained to operate within a certain range. If the climate system really was that sensitive, it would have forced itself into oblivion long ago.
http://www.drroyspencer.com/2009/05/the-mit-global-warming-gamble/
Testimony of Roy W. Spencer Before the US Senate EPW Committee: Latest Research on Climate Sensitivity to CO2
http://jennifermarohasy.com/blog/2008/07/testimony-of-roy-w-spencer-before-the-us-senate-epw-committee-latest-research-on-climate-sensitivity-to-co2/
5. It is not generally acknowledged, including by either Roy Spencer or Ferenc Miskolczi, that their important work fits neatly together or supports the Gaia theory, this is my opinion.
I have relied to a large extent on a series on ABC radio two summers ago and Wikipedia for my understanding of Gaia as described by James Lovelock. I have not read any of James Lovelock’s books. I am more familiar with the work of Tim Flannery and have read the ‘Weather Makers’. http://en.wikipedia.org/wiki/Gaia_hypothesis
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Jen,
FM’s stuff is hardly new any more – it’s been around for over a year, and thrashed to death on the blogs. You’ve even had a belated thread on it here.
And he hasn’t shown, by new research that the atmosphere maintains a ‘saturated’ greenhouse effect maintained by water content. He has baldly asserted, with no backing, that the optical density has to find a level to maintain optimal cooling. Your notion of water vapor control is not what he is saying at all. FM is saying that this optical density requirement controls the water vapor. And it’s a global average, clear sky grey-gas OD. Somehow the Earth adds up that highly theoretical construct, then makes it rain just the right amount.
I don’t think you’ll find any enthusiasm for FM theory from Roy Spencer.
This loose claim that natural systems always show negative feedback is not only an unscientific argument, but is wrong. Any combustion process has strong positive feedback. Even composting.
Correction – in the above, optical depth would be a better term than optical density (although they are related).
Ahh Jen – I’m no Gaia-ist, but your mistake is to think that Gaia self regulates the planet according to what constitutes a liveable environment for humans. A cursory glance at history should remind us all that this is not the case.
Ahh MattB – I’m no Gaia-ist either. And I am a bit confused by James Lovelock in so much as he has written that the concept is not teleological (the universe is directed towards a final purpose) but his language is.
Jennifer,
I’ve heard Lovelock at a conference state, that the earth is not alive and that he never meant it as such. I’ve set out on this blog before that at the same conference Lovelock explained that the name “Gaia” wasn’t his but suggested by an author living in the same village as Lovelock, if my memory is correct, Lovelock said it was the thriller writer Len Deighton.
As an engineer I deal with systems all the time that regulate themselves and we now borrow lost of concepts from nature to extend both design and self regulation, I have no problems with things regulating themselves and not being alive but then I am extremely sceptical about artificial intelligence when we don’t even know what consciousness is.
As to teleological (I take it you are using it separate from the idea of a lump of rock being alive) but are you confusing outcome with purpose?
A related approach is the Iris effect published by Richard Lindzen of MIT:
http://ams.allenpress.com/perlserv/?request=get-abstract&issn=1520-0477&volume=082&issue=03&page=0417
Open the pdf to read it
“If you find the Buddha on the road, kill him”.
Lovelock can claim he never meant for Gaia to be mistaken as a literal concept, but he has made a fortune promoting exactly that.
Now Lovelock is a transparent misanthrope, betting on the xenocide of humans.
As much as the AGW community seeks to pretend he is not one of the founders of apocalyptic environmentalism, they are stuck with him. Just like Hansen and Gore & pals, Lovelock is one of the spokesmen for the AGW movement.
AGW depends on radical changes in the way Earth reacts to CO2. Reminding people that negative feedbacks have prevailed, and will continue to prevail, is always a good effort.
Nick:
“This loose claim that natural systems always show negative feedback is not only an unscientific argument, but is wrong. Any combustion process has strong positive feedback. Even composting.”
Hmmm, Are you sure about this? Combustion (and composting) reach a maximum intensity. There is no “tipping point” or run-away there 🙂 Either fuel or oxygen create a limit.
It is pretty clear in my mind that any postive feedbacks, if there are any, must be quite limited, since the Earth has been around in roughly the same form for eons. It is also pretty clear to me that water doesn’t provide a positive feedback, because the temperature in the tropics over water NEVER goes much above 33-34 C (and I’ll bet it hasn’t ever gone much below that, either).
jae, positive feedback with runaway usually has exactly that effect, that a system moves rapidly from one state to another where something limits rate of change. The wellknown howling microphone, for example, reaches a finite loudness at which it is limited by clipping or amplifier power.
Hmmm, Are you sure about this? Combustion (and composting) reach a maximum intensity. There is no “tipping point” or run-away there 🙂
ever seen a haystack catch on fire and burn down the hayshed? I’d say that’s a tipping point.
The wellknown howling microphone, for example, reaches a finite loudness at which it is limited by clipping or amplifier power.
it’s limited by blowing the speaker cones out of the speaker so the whole system collapses.
Based on studies of Venus it is believed that greenhouse warming is responsible for the elimination of liquid water from the planet, leaving only trace amounts of water vapor in its atmosphere. There is no physical basis for a theory that planetary systems will automatically stabilize themselves. Venus is a counter example. The only way to look at this is to use physics and whatever empirical relationships that are required to simulate the systems and see what happens.
This is what climatalogists do. The proof is in the results.
It is pretty clear that the work of Miskolczi is flawed because he assumes what he is trying to prove, ie that optical depth has a upper limit.
“There is no physical basis for a theory that planetary systems will automatically stabilize themselves. Venus is a counter example.”
Venus is extraordinarily stable. In fact if you actually look at the data; at the level where Venus’ atmospheric pressure is the same as Earth’s the temperature is similar.
Rather than deny natural climate change like the religious fundamentalists on this blog I’m a firm natural CC believer.
Over at WUWT Anthony has posted some interesting info with graphs showing that the NH recorded the highest january snow cover in at least 30 years.
The antarctic has recorded an increase in ice extent of 100,000sq klms every decade for the last 30years.
The artic ice extent is at the highest May recording since satellite records began.
Yet we’re about to blow trillions worldwide on a stupid theory flogged by numbskulls for zero return when we should be be using a fraction of that amount to pursue e.g. better, safer nuclear technology, more nano battery innovation and perhaps solar, to electric to hydrogen technology for domestic use around the world. ( UNSW)
Nick:
What energetic process would you describe as not having “positive feedback,” by your definition? All processes are limited in some way.
adler:
“The only way to look at this is to use physics and whatever empirical relationships that are required to simulate the systems and see what happens.
This is what climatalogists do. The proof is in the results.”
LOL. Can you show us even one “result?”
Running out of fuel (which is what happens in a combustion system) is not the same as having a negative feedback.
Jae,
Well, there’s usually a mixture of feedbacks. Processes dominated by negative feedback tend to be boring – nothing is happening. We notice positive feedback more.
A wood fire is an example. You start with some fuel which, as boy scouts know, is often in a fairly stable state. The rate of heat loss by radiation and conduction rises with temperature – a negative feedback. But if you huff and puff enough, you can move to a point where the rate of oxidation has an exponential dependence on temperature, when positive feedback dominates – hotter so faster oxidation so more heat production so hotter…. The fire grows rapidly through this positive feedback, until it is limited by the rate at which air and fuel can mix. Then, for a while, there is a new stable state. If the temperature rises, the nearby air is oxygen-depleted, which slows oxidation.
Jan Pompe wrote:
Venus is extraordinarily stable. In fact if you actually look at the data; at the level where Venus’ atmospheric pressure is the same as Earth’s the temperature is similar.
It may be stable today, but the historical evidence is that there was liquid water there in the past, that was evaporated by a runaway greenhouse effect, dissociated and the hydrogen passed into outer space due low molecular weight and the effect of solar wind.
http://www.spacetoday.org/SolSys/Venus/VenusPlanet.html
The temperature altitude profile of Venus is a function of the constituents of its atmosphere which is different in composition from earth. The albedo associated with sulfate clouds on Venus is much larger than earth. The similarity you remark on is a result of coincidence and the correspondence is not exact. What importance do you ascribe to this observation?
Comment from: jae May 27th, 2009 at 9:50 am
adler:
“The only way to look at this is to use physics and whatever empirical relationships that are required to simulate the systems and see what happens.
This is what climatalogists do. The proof is in the results.”
LOL. Can you show us even one “result?”
All model runs show that increases in CO2 will result in temperature increases over a long period of time. Variations in empirical parameters change the amount of the temperature increase.
The models do not show agree with Miskolczi’s idea that the greenhouse effect is capped.
Nick; as far as I can recall you have not commented on Steve Short’s alternative thesis to M’s equilibrium theory; to remind others Steve calculated that M’s Tau or constant optical depth, which is the measure of the greenhouse effect [because the higher it is the more times a photon undergoes absorbance and transmission between the surface and the TOA; in the warmist parlance, the more ‘trapping’ is taking place], only is constant at a clear-sky or near clear-sky circumstance. For all other more common [cloud] situations the Tau actually increases; but as cloud cover increases the water relevant emission from the tops of the clouds increases [ET_U] too because more water is used forming the [low] clouds and even though the TOA window S_T declines the increase in ET_U combined with the decline in S_T maintains the equilibrium; Steve calls this the real E_U or rE_U; the equlibrising ‘mechanism’ is the K factor of M’s theory; this is the non-radiative transfer of heat energy by evapotranspirational methods from the surface to the cloud[formation].
I had a couple of queries about Steve’s thesis; namely that A_A could still equal E_D under the clouds; and secondly, while OD may fluctuate between the under and above clouds [?] overall it still conform to M’s Tau; the innovation in Steve’s thesis is the working of K, the increased cloud cover, the marrying of non-radiative energy transport below the clouds with increased radiative transport [at water wavelengths, which dovetails with Mike Hammer’s recent water paper] so that the decline in the window [due I presume to extra CO2; the non-absorbed wavelengths would still have the same window but it would be proportionally smaller] is compensated by the expansion in the water ‘window’.
The Gaia concept and indeed feedbacks are a red herring to all this because what [arguably] is happening is simply what physically happens with slight extra warming on a water planet with evaporation and transpiration. M’s theory, Steve’s variation on M and MEP are all attempts to wrap that process up. At the end of the day AGW simply is not happening either in terms of the transient climate response and I would dearly love someone to tell me when the [new] equilibrium climate sensitivity [ECS] point is going to be achieved.
How about “entropy”? How come that factor does not come into the picture? Is it not a factor that could lead to unstability? As the energy converters (biota) are increasing in number, and as their need for better living circumstances is very much related to more energy conversion and as we cannot convert all the energy we utilize to usefull work, whats going to happen when world population reaches 9.5 billion? Just asking.
Best regards to all. This post and comments are very informative for me.
“It may be stable today, but the historical evidence is that there was liquid water there in the past, ”
What???
There is supercritical liquid CO2 there NOW!!!! That site you linked is pure speculation.
The CO2 connection and Venus is bunk for a number of reasons; firstly Mars has ~ the same amount of atmospheric CO2 as Venus 95% cf 96% yet Mars has no warmth in its atmosphere; also, in previous geologic eras the Earth had very high atmospheric concentrations of CO2; Scotese and Berner data show about 7000 ppm, while Plimer shows sources even higher; if runnaway to Venus was going to occur as Hansen argues it would have already.
Dr Craig O’Neill in Australasian Science, vol 29, no 3, April 2008 shows that Venus has a tectonic process called ‘episodic overturn’ whereby over relatively short geologic spans the whole surface is recycled through volcanism; on this basis Venus never stood a chance. The final nail in the coffin is the atmospheric pressure of Venus; in this respect it is not the greenhouse effect of the CO2 but its pressure; for a couple of interesting takes on this see;
http://www.geocities.com/atmosco2/atmos.htm?200820
http://www.ilovemycarbondioxide.com/pdf/Rethinking_the_greenhouse_effect.pdf
Just filing this here:
“I don’t see any conflict between Roy’s and Ferenc’s work. Roy (and Richard Lindzen with his Iris effect) has been looking at the short term or intra-seasonal effect and Ferenc and the “steady state” or long term multi-decadal effect. Let’s not fool ourselves that there
must be only one “regulatory” method in a system that has a number of dissipative processes operating on different time scales.”
Jan Pompe
Nickolas:
” wood fire is an example. You start with some fuel which, as boy scouts know, is often in a fairly stable state. The rate of heat loss by radiation and conduction rises with temperature – a negative feedback. But if you huff and puff enough, you can move to a point where the rate of oxidation has an exponential dependence on temperature, when positive feedback dominates – hotter so faster oxidation so more heat production so hotter…. The fire grows rapidly through this positive feedback, until it is limited by the rate at which air and fuel can mix. Then, for a while, there is a new stable state. If the temperature rises, the nearby air is oxygen-depleted, which slows oxidation.”
Er, you did NOT answer my question at all. You just erected another strawman!
Eli-bunny:
As usual, your comments are irrelevant, but contrived to make everyone shake their head and go away. You are a very devious bunny-fuck, IMHO.
Nickolas:
” But if you huff and puff enough, you can move to a point where the rate of oxidation has an exponential dependence on temperature, when positive feedback dominates – hotter so faster oxidation so more heat production so hotter…. ”
Err, this is NOT positive feedback, this is “stoking the fire.” There is a big difference, Nickolas. If I add solar insolation to the Earth-system, that is NOT positive feedback, either. Do you have any examples of naturally positive feedback? I thought not.
Addled Adler:
“All model runs show that increases in CO2 will result in temperature increases over a long period of time. Variations in empirical parameters change the amount of the temperature increase.
The models do not show agree with Miskolczi’s idea that the greenhouse effect is capped.”
Another BIG LOL, bro. The models have ALL been invalidated by the lack of a statistically significant warming for the last 15 years and a STEEP TREND OF COOLING FOR THE PAST 7.5 YEARS, IMHO. Just where the hell is that EMPIRICAL data that you reference, sir? Maybe you should stop reading RC and the other non-scientific communist blogs, and read Anthony Watt’s, Lucia’s and Roy Spencer’s blogs for awhile. Anyone who really believes the output of those compute models has an addled brain. Again, IMHO.
Cohenite, Yikes!
“The CO2 connection and Venus is bunk for a number of reasons; firstly Mars has ~ the same amount of atmospheric CO2 as Venus 95% cf 96% yet Mars has no warmth in its atmosphere; also, in previous geologic eras the Earth had very high atmospheric concentrations of CO2;”
Mars has waaaay less Co2 than Venus in its atmosphere due to the low pressure. However it still is true that on Mars the mass of Co2 over every square meter is 30 to 40 times that of Earth.
I still think the proper Earth – Mars comparison needs to be done. About the same axial tilt, about the same LoD, Mars gets half the insolation of Earth and nothing much else to upset whatever temperature effect Co2 has. Like no oceans or significant water vapour. Construct theoretical models of Mars with current atmosphere and one with same density but nitrogen instead of Co2.
Yikes Eyrie, I agree with you but we are approaching the same thing from different points of emphasis; as a % of the atmosphere CO2 is 95% on Mars, on Venus 96%; BUT Venus is a much heavier and dense atmosphere so the total CO2 in Venus’s atmosphere is much greater than the gross total in Mars’ atmosphere; my point was that atmospheric pressure on Venus and Mars is a [the] contributing factor to the atmospheric temperature profile of the 2 planets; as possibly on Earth, although this is ignored by the AGW crowd; CO2, as a % or in gross quantity seems to play little role in that temperature profile after some small intial imput.
cohenite wrote:
“The CO2 connection and Venus is bunk for a number of reasons; firstly Mars has ~ the same amount of atmospheric CO2 as Venus 95% cf 96% yet Mars has no warmth in its atmosphere; also, in previous geologic eras the Earth had very high atmospheric concentrations of CO2; Scotese and Berner data show about 7000 ppm, while Plimer shows sources even higher; if runnaway to Venus was going to occur as Hansen argues it would have already.”
You’ve understated the case. The sun is the 800-pound gorilla of climate. Venus is roughly half of the Earth’s distance from the sun. Because of the inverse-square law, it gets roughly 4 times the intensity of solar radiation that our planet does. Please pass the marshmallows and the barbecue sauce.
The Lovelock treatise is an opportunistic, simplistic summary of prior observation and as such has no quasi religious or supernatural significance whatsoever.
For example, any thinking person would know that there are chemical, physical, mathematical reasons why most humans look alike, are roughly of the same weight and height and so on. Of course there are feedbacks about equilibrium positions. Try giving rodents liquid diets, not abrasive ones, to see how fast their teeth grow.
Humans are not identical to each other. Some get sick. Disease can sometimes be equated to a feedback that has gone too positive like cancerous growths or too negative like anorexia (simplifications here).
There is a whole set of mathematics around the predator/prey relation, which gets interesting when considering parasites that need a host to survive, yet kill the host. A runaway scenario can develop in which one or the other is extinguished. The vast majority of past species are extinct, yet old Mother Earth just keeps rollin’ along. One might expect this climate constancy from a stable sun orbiting a quite stable Earth. One has to separate life forms from non-life. They can’t be thrown together into one unified theory.
Life? Cogito ergo sum. From a geat mathematician.
In a sense, when dealing with earth science, the equilibrium state is not closely defined, but there is no evidence of huge internal excursions. The study of exceptions to the equilibrium state can hold the most fascination. I spent 30 years looking for ore deposits, which are just that.
Conversely, the thrust of many climate publications is to do away with anomalous states and variation. The handle of the hockey stick has to be made linear at huge cost to integrity. Representations of lines, areas and volumes have to be smoothed, dumbed down to a Valium-like state before they can be accepted by the devoted. This is what I can’t understand.
What motivates these people who have inserted religious attitudes into pre-existing sane science? People might have an interest in both religion and science, but the result of their crossing is disaster. Like the Gaia idea, not good enough to call an hypothesis.
Jan’s CO2 on Mars is a good ruse. A Sinkers fav too. So there’s more atmospheric CO2 on Mars than Earth sinkers will tell us. So why isn’t it warmer. Perhaps it’s as warm as it should be?
Further from Sun, but darker albedo, but thinner atmosphere, but more CO2.
How warm would you like it to be guys. Got a formal calculation?
Coho,
“Nick; as far as I can recall you have not commented on Steve Short’s alternative thesis”
No, I haven’t. Steve has kindly sent me a spreadsheet, which I have been working through, and I’ll probably raise direct questions first with him, to minimise red herrings. But my impression is that it should not be seen as the new FM theory. It is less ambitious, less speculative – more a collection of probably sensible estimates.
A useful distraction luke; if g = the surface gravitational acceleration, P = surface atmospheric pressure, h = height above planetary surface and T = temp in K, then;
P(h)/P(0) = e to the -h/Hp, where Hp =
kT/,umug where k = SB’s constant and ,u = the mean molecular weight of the atmospheric gases and e = the exponential decrease in pressure and density of the atmosphere.
What you have to remember is that the atmospheric pressure at the surface of any planet = the weight of the overlying atmosphere; so this must also determine temperature.
Nick, A summary from you or Steve on the “less ambitious, less speculative” theory/hypothesis for posting at this blog would be great?
Isn,t this the same guy (Tim Flannery) that said that we would see no more rain in NSW and QLD? BTW NSIDC, NANSEN etc… have pulled the plug on ALL ice data since start of May.
http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
Judging from curent CT pics, NH is now =NORMAL or slightly above anomaly…AGW = Dead
http://arctic.atmos.uiuc.edu/cryosphere/
Jen,
I think that would need to come from Steve, and I think he may be still polishing it.
Luke are you sure I metioned CO2 on Mars or perhaps the context was another planet?
Perhaps Adler has addled your brain.
cohenite
“What you have to remember is that the atmospheric pressure at the surface of any planet = the weight of the overlying atmosphere; so this must also determine temperature.”
Actually I think you might find the pressure a little higher one might suppose that the impact of the particles travelling at ~500m/s might add a little for to what they would if they were at rest and the atmosphere a solid.
Jae “Er, you did NOT answer my question at all.”
OK, I’ll expand. With the campfire, initially there are at least two feedback paths. Heat loss by radiation and convection increases if the temp rises, causing cooling. That is a negative feedback. Heat generated by oxidation rises with temp. That is a positive feedback. However, oxidation at ambient is very slow, so the negative feedback dominates.
Firelighting activity is designed to increase the positive feedback, by raising the temp, and also to reduce the negative, by stacking the fuel to deter radiative escape, for example. If this is successful, then not only do you get nett positive feedback, but it reaches a tipping point (“thermal runaway”, say). The fire then spontaneously grows, and you can stop puffing.
This runaway stage slows when the products (eg CO2) increasingly block access of oxygen. Since the rate of generation of products depends on rate of combustion, you can see this as a growing negative feedback, which creates a new stable state – a steady fire.
So that’s the answer – there’s usually an interaction of positive and negative feedbacks, which we have in the atmosphere too.
Nick can you do that with a little more rigour I’d like to see some equations.
Jan,
This isn’t a very equation-friendly environment, and a campfire isn’t mathematically simple either. But the most important equation comes from our old friend Arrhenius. It shows how the reaction rate depends on temperature. What counts for the strength of positive feedback is the gradient of the curve. So for small T (ambient for a fire) there’s no significant reaction, and hence very little gradient, but there’s a region where it is rising very rapidly.
OK, Nick, I see what you mean. When I have some beer, I experience all kinds of positive feedback, but if I have too many, it goes negative.
Jae,
Exactly, and you reach a new stable state.
OK, now I’ll pretend I’m Mutha’ Earth and I’m in a new stable state. And the source of the supposed “feedback” (OCO/HOH) continues to increase. But, alas, I’m colder than I was the year before. And the year before that. And the year before that….. How did I get to this new colder stable state, if there is an amplification of temperature by a positive HOH-vapor feedback? WTF, Oracle-Nick? Do you have any clue? Your religion depends upon some new revelation from Gaia, I think.
jae, chemically combustion and explosions are pretty much the same thing. Roughly speaking, you can divide the processes into initiation, chain reactions involving free radicals formed in the initiation and their consumption in termination reactions. What determines the rate is the balance between the rate at which the radicals are formed and the termination reactions. In combustion the rate of forming free radicals and their disappearance balance and the amount of heat released and the number of free radicals formed reaches an equilibrium and stays roughly constant until all the fuel is consumed. In an explosion the amount of heat generated and the number of radicals grows exponentially until all the fuel is consumed. In both cases the feedbacks have nothing to do with the amount of fuel but when you use it all up the music stops.
Such a joy agitating you.
“Your religion depends upon some new revelation from Gaia, I think.” A stable state was being referred to, not a transitory spike.
Co, you know that saying
“The CO2 connection and Venus is bunk for a number of reasons; firstly Mars has ~ the same amount of atmospheric CO2 as Venus 95% cf 96% yet Mars has no warmth in its atmosphere; ”
just shows how silly you are. The percentage has nothing to do with the case, the absolute amount everything. Venus has a very dense atmosphere, Mars, well Mars’ atmosphere at times is purely honorary, certainly in the winter when it pretty much disappears.
Hi Mr Bunny I was about to thank Nick for his reply and tell him that look at Arrhenius Eqn I see no feedback there only chain reaction but I think you have already made the point I was going to make so I’ll thank you as well.
I did so enjoy in my youth (when not playing with jack hammers, gelignite, ammonium nitrate and detonators to clear subdivisions and cut roads through hillsides) to fill up paint tins, with hole in lid and side near the bottom, with flammable gas and ignite the gas at the hole in the top :- then wait for the proper balance …. then BOOOM!
The serious point of the anecdote of course is that it is not feedback (positive or otherwise) but when the mixture was right after some of the gas had burnt and replaced by air it would explode. I’m sure jae is quite familiar with chemical reaction rate equations I’m pretty sure from my foggy memory from my time before boredom caused me to bolt from the chem lab that getting reactions rates and times right is pretty important for polymer manufacture.
“just shows how silly you are. The percentage has nothing to do with the case, the absolute amount everything. Venus has a very dense atmosphere, Mars, well Mars’ atmosphere at times is purely honorary, certainly in the winter when it pretty much disappears”
eli, do keep up; my 3.14pm comment;
“Yikes Eyrie, I agree with you but we are approaching the same thing from different points of emphasis; as a % of the atmosphere CO2 is 95% on Mars, on Venus 96%; BUT Venus is a much heavier and dense atmosphere so the total CO2 in Venus’s atmosphere is much greater than the gross total in Mars’ atmosphere; my point was that atmospheric pressure on Venus and Mars is a [the] contributing factor to the atmospheric temperature profile of the 2 planets; as possibly on Earth, although this is ignored by the AGW crowd; CO2, as a % or in gross quantity seems to play little role in that temperature profile after some small intial imput.”
And who said I wasn’t silly; I’d have to be knocking heads with the likes of you and those nasty brethren of yours at Deltoid.
I find it interesting that the International Standard Atmosphere for Earth assumes a lapse rate of 2 deg C per thousand feet in the troposphere. Very close to the saturated adiabatic lapse rate. Yet again water dominates the atmosphere of this planet up to the tropopause.
I have no idea if anyone has defined a standard atmosphere for Mars although future Mars aircraft probe designers must be using something. I find Venus an uninteresting case. Weird planet. Retrograde resonance locked rotation. etc. etc.
Yeah right Eli – Mar’s atmosphere disappears in winter. Winter ain’t global, pal. Still 30 to 40 times the CO2 per square meter as Earth. Should be a really great greenhouse effect then.
Nick and others,
If natural systems don’t tend to an equilibrium – your claim – then wouldn’t it be reasonable to expect climate change – in short why are governments trying to stabilize the current climate?
Jennifer,
I don’t think anyone says there can’t be natural climate change. Things like ENSO cycles, or in the much longer term, ice ages, are well recognised. In fact cycles generally have an underlying positive feedback mechanism which determines the frequency.
And I don’t think governments are trying to stabilise the climate, in the feedback sense. There’s debate about how stable it is, but not about trying to change that.
The debate is about a specific driver, GHG increase. That isn’t a feedback or an oscillatory process. It’s a one-way push, caused by mining carbon, and the climate can only respond by getting warmer in the long term. Feedbacks influence how much warmer.
A rough analogy is a kid on a portable swing. Gravity, momentum/ke etc maintain a fairly stable oscillation. But they don’t help if someone picks up the swing and moves it. The oscillations will go on, but with a new central point.
“Thing like ENSO…are well recognised.” Well, Nick I just spent a very invigorating period at Deltoid where sod and other lumps of dirt argued that ENSO doesn’t exist. On issues more salubrious, the problem for GHG driving is that there is no Transient Climate Response and noone knows what and when the Equilibrium Climate Sensitivity will be at or after or during the nominated red button of 2CO2; although the boys at MIT get into the swing of things and took a stab at it;
http://wattsupwiththat.com/2009/05/26/how-not-to-make-a-climate-photo-op/#more-8038
As I said at Deltoid, which seemed to stir the creatures up more than usual, I’d love to get some of these doom and gloom, end of the world ‘experts’ in court. It’s about time some responsibility attached to ‘expert representation’.
Nick I’m really mystified as o where you are getting this from:
“In fact cycles generally have an underlying positive feedback mechanism which determines the frequency.”
Yes electronic oscillators have positive feedback but not every cyclic behaviour involves feedback for instance a spinning wheel is cyclic, a pendulum the orbit of the moon affecting the tides the orbit of the earth affecting the seasons these are all cyclic but they are all also open loop i.e. no feedback involved. You might make a quasi sort of negative feedback from the damping but that’s really open loop as well.
Thank you Eli (and Jan). Of course, I understand those reactions extremely well. I’m just not used to viewing them in “feedback” terms. Indeed, I made a lot of nitro-polymers in my time. You cannot even touch some of them, without worrying about “feedback.”
Nick:
” In fact cycles generally have an underlying positive feedback mechanism which determines the frequency.”
Now, it cannot always be a “positive” feedback if you have “cycles,” correcto? And it sure appears that there is something going on that is MUCH more powerful than CO2 (which probably has no power at all), since temperatures are decreasing at a steep rate for about 7 1/2 years! I’m still awaiting an explanation of this from an AGW-phile.
“I’d love to get some of these doom and gloom, end of the world ‘experts’ in court. It’s about time some responsibility attached to ‘expert representation’.”
Oh yes Cohers – and we’d love to get all the political Australian sceptics “reviewed” thoroughly too with doors bolted. Should be a major blood bath. You perhaps might offer yourself up? 🙂
You might have something here luke; instead of this namby pamby debate and screeching at each other, perhaps a few organised one on one biff events might be the answer; if the sceptics win the AGW crowd are given 30 acres at Nimbin with a big fence around it and they commune with nature without bothering anyone else; if the AGW crowd win then the sceptics go and live in a coal mine. What weight division are you?
oh – I was thinking a serious session where operational CSIRO scientists get to grill the sceptics.
Ho ho ho ! (and vice versa). Will probably come to this eventually.
Kinetics can be expressed as a series of differential equations. Radical formation is a feedback. The classic example is a mixture of H2 and Cl2
Cl2 + UV light/heat/spark –> Cl + Cl (Initiation)
Cl + H2 –> HCl + H
H + Cl2 –> HCl + Cl Propagation
H + H + M –>H2 Termination
Cl + Cl + M –>Cl2
H + Cl + M –> HCl
You need a third body for the termination steps
The Cl and H produced in the second and third reactions are feedbacks. The temperature rise from those reactions dissociates more Cl2 etc. That is also a feedback.
There is even a movie
http://chemed.chem.purdue.edu/demos/main_pages/10.7.html
Luke the warmer-preacher:
“oh – I was thinking a serious session where operational CSIRO scientists get to grill the sceptics.”
Hmm, it would be fun to watch the “operational CSIRO scientists” try to do this. I never yet saw an example of where a “skeptic” was “grilled” and he didn’t blow the “competition” away with facts and logic (that is because the AGW “side” doesn’t have any empirical data or logic to support its position, just computer models and emotional rhetoric, after all. Thus, they always resort to “bumper sticker arguments” and something like pictures of polar bears drowning). In the USA we cannot even get ONE of the chicken-shit AGW priests to stand up in public for a debate with a skeptic. For example, Monkton recently spent a lot of $ to fly over here because of an invitation to debate Gore, but the Democrats cancelled the debate. I wonder why? Are they afraid? Answer: Of course they are afraid, since the emperor is really, really naked.
Luke, I challenge you to cite a debate between “skeptics” (i.e., realists) and the leftist, communistic AGW freaks wherein the AGW-freaks don’t make a complete ass of themselves to the average bystander. Hansen, Gore, and the rest of the hypocritical jokers, like all leftists, are good at bumper sticker slogans, but mighty poor on the real battlefield.
Eli: Nice, but you forgot the important stuff–the dots for the free radicals (the free electrons, man). It’s Cl. Not Cl. LOL. Do you need any references?
More correctly, the “unpaired electrons,” which are what make “free radicals,” well, RADICAL, dude. I love it when a peer tries to lecture me, LOL. You are on my turf, bunnyradical.
Well yes Jae – indeed this encounter is an embarrassment to right wing denialist turds everywhere. Enjoy:
http://rationallythinkingoutloud.wordpress.com/2007/07/17/abc-australias-tony-jones-and-the-great-global-warming-swindle-debate/
Tony Jones a great Australian journalist? Who knew? Left wing prat is more like it.
jae ” I’m just not used to viewing them in “feedback” terms.”
That’s because it isn’t.
Eli “The Cl and H produced in the second and third reactions are feedbacks. The temperature rise from those reactions dissociates more Cl2 etc. That is also a feedback.”
No Eli that’s just chain reaction. Just because a reaction can be described by differential equations doesn’t mean there is feedback involved.
Luko:
“Well yes Jae – indeed this encounter is an embarrassment to right wing denialist turds everywhere. Enjoy:”
I pity your ability to distinguish truth from blatant nonsense. Although there were a few errors in “swindle,” the main message is unassailable.
Now, perhaps you can shed some light on just why the Earth is cooling, big time, despite increasing CO2 emissions. None of the rest of your geniuses has come forth. Is there maybe something “greater than CO2” in climatology? How about the SUN, AGW-TURD?
Jan:
“That’s because it isn’t.”
Yeah, I sense that, too, but I’m having trouble defining my own terms here. I think the normal reactions that increase entropy should not be considered “feedback.” There has to be an additional parameter that is causing the feedback. For example, the Sun heats the atmosphere and all the molecules in it. The simple heating of the atmosphere by the Sun is not “feedback” (same as the case with combustion–the simple oxidation of all the carbon and hydrogen is not feedback, just a normal chemical reaction). ONLY if the resultant heat causes some OTHER “third” effect, like evaporating water, AND that effect (water vapor) somehow enhances the heating, then that would be “feedback.” That is what happens with the PA system. The amplification of the sound is not “feedback.” It is the extra energy that enters the microphone from the speakers that is the “feedback.” And like you have said always, that requires that ADDITIONAL energy be added to the system. Don’t know how to explain it better….
Mate if you believe Durkin’s dross you have definitely come down in the last shower. Wanker.
jae “Don’t know how to explain it better….”
Neither do I and feedback is my turf.
” like evaporating water, AND that effect (water vapor) somehow enhances the heating”
Yes that could be considered feedback I don’t however think that it will be positive and that it will enhance heating.
People should not confuse heat, energy and temperature a rise in temperature does not necessarily mean that there is more energy available for work or even more in in the system.
Comment from: Eli Rabett May 28th, 2009 at 2:14 pm
How do you account for the observation that a usual product of a free radical reaction is another free radical? (Hence catalysis using free radicals). What mechanism causes a reduction in free radicals to end your postulated scheme?